     (not (#+clj identical? #+cljs keyword-identical? op :is))
     (update-in [2] collect)))
 
-(defn applicable-delta
-  "Bring a delta from diagnostic form into applicable form."
+(defn summable-delta
+  "Make a diagnostic applicable for add again."
   [[op korks new-val :as delta]]
   (if (seq korks)
     delta

    (add-root-delta val op korks-or-new-val)))

(defn add
  "Reducing function to apply a delta to a streamed compound EDN
  value."
  ([] nil)
  ([val] val)
  ([val [op & maybe-deltas :as delta]]

  [ks]
  (if (coll? ks) ks [ks]))

;; Adding deltas
(defn- add-root-delta
  [val op new-val]
  (case op
